‘Whatever it was, it affected his breathing so we had to leave him there while they tried to find out what was wrong.’

Michelle Coward, of Beech House surgery, treated the dog.

She said: ‘Trevor was presented to us with signs of severe air ingress under the skin. There were no external injuries that would explain how air had got under the skin, so we suspected that an internal injury to the airway or oesophagus could have been allowing the air to leak into the body.

‘Every time he took a breath, some of the inhaled air escaped through a hole in his windpipe around the muscles and fatty tissue under the skin, and X-rays showed the emphysema was worsening.